My wife was told she had uterine polyps following a hystercopy where a biopsy was taken. we assume of the polyp. this has come back as atypia complex hyperplasia. clearly a biopsy is taken from one tiny bit what are the chances of it present in womb?

Uterine polyps originate from the tissue inside the womb. Please discuss the findings with the treating doc.

Womb is a nonspecific lay term, generally equivalent to uterus, so it is not clear what distinction you are trying to make. The diagnosis you provide is considered precancerous. Follow up management needs to be discussed with your doctor.

If the whole lesion was not removed, it would be prudent to visit the treating doctor and consider having rest of the lesion removed.

Follow Up and discussion with the treating physician will be most helpful to clarify complex medical terms and concerns. The trust you have on the doctor who performed the procedure is best and direct mean of communication.